1. Field of the Invention
This invention relates to a device for positioning human legs in preparation for the taking of X-ray films.
More particularly, the invention relates to a device of the above character which permits the taking of X-ray films of legs held in forced extreme joint positions, especially for the purpose of diagnosing ligamentous damage.
2. The Prior Art
Certain diagnostic X-ray examinations of the human leg can be made only when the leg is held in specific, defined positions. This is particularly true of the diagnosis of ligamentous lesions (i.e., ruptures of the ligaments) in the leg. A device for holding the leg for this purpose has been described in Helv. CHIR. ACTA 43, 195-203, 1976. In this device the lower part of the leg is placed on a tubular steel bracket and the heel rests in a V-shaped bracket which is secured to and projects laterally from, a leg board. On the other side of the board, as considered with reference to the foot, a member is mounted which can be turned in opposite directions, depending upon which leg is being examined, so as to properly position an ankle joint in the path of laterally impinging X-rays. Laterally mounted on the board is a holder for the X-ray film. Two straps on the tubular steel bracket serve to urge the lower part of the leg downwardly with respect to the fixedly positioned foot.
This prior art device is suitable for exposing relative displacements of talus and fibia (known as the "drawer phenomenon") to the X-ray equipmemt, and to show that (or whether) there has been damage to the ligamentum fibulo talare anterius.
There are, however, two problems: the device cannot be used to provide exact proof as to whether damage has been sustained to the ligamentum fibulo calcaneare, and the degree of displacement between talus and fibia depends upon the pressure exerted by the straps. Since this pressure cannot be reproduced exactly on the occasion of different examinations, it follows that the original X-ray picture also cannot be exactly reproduced. This, however, is necessary to permit comparison pictures to be made of the other, healthy foot and to enable the diagnostician to compare a final, post-treatment X-ray with the original picture to draw conclusions as to the corrective results obtained.